I use a reef octopus calcium reactor along with a master flex pump. When I first got it I didn’t like it much as my flow rate would keep slowing down, even when I had the effluent wide open. I gave in and bought the master flex pump and things are very, very stable now.
If you were going to go with a calcium reactor I feel you need a good dosing pump along with a good regulator. If you don’t you will more than likely have to check effluent often. I haven’t had to touch my effluent in 9 months. All I do now is turn the little knob on the regulator to allow more co2 if alk is dropping.
This is my calcium reactor.
https://www.aquacave.com/reef-octop...r-5-5-dual-chamber-with-pump-by-coralvue.html
I honestly don’t care for the BC one. I really dig the Greg C one and its tips are a lot more blue in person than that pic shows. I was kind of bummed I couldn’t get the blue to show up.